A man suffering from actinic reticuloid for 2 years showed highly abnormal light sensitivity over a broad action spectrum. He has been successfully treated with daily whole-body topical applications of mechlorethamine, initially for 4 weeks and after a 2-month interruption, for 3 weeks. Gauzes moistened with the same solution were placed over lichenified areas for 10-15 min. His skin became normal pale and the lichenification decreased. After treatment his tolerance for daylight increased.